Alternating-current induction-motor.



PATBNTED AUG. 1, 1905;

L. SGHULER. ALTBRNATING CURRENT INDUCTION MOTOR.

AP?LIUATIOF FILED JULY 16, 1904.

S'VtWWtOZ Leo Schollen.

ANDREW n GRAHAM co. Mmuun menu-"Fm W/SHINCTON. a c.

UNITED STATES PATENT OFFICE.

ALTERNATlNG-CURRENT INDUCTION-MOTOR.

Specification of Letters Patent.

Patented Aug. 1, 1905.

Application filed July 16, 1904. Serial No. 216,920.

To all whom, it may concern:

Be it known that I, LEO SOHULER, a subject of the King of Prussia.German Emperor, residing at the city of St. Louis, in the State ofMissouri, have invented a certain new and useful Improvement inAlternating-Current Induction-Motors, of which the followingis such afull, clear, and exact description as will enable any one skilled in theart to which it appertains to make and use the same, reference being hadto the accompanying drawings, forming part of this specification.

My invention relates more particularly to induction alternating-currentmotors of the type designed to produce high torque and low currentconsumption at starting. Such motors usually have a starting resistanceconnected in circuit with the induced member or armature at starting andthe armature-winding is short-circuited at a small number of points(usually three) when normal working speed is attained.

The object of my invention is to increase the number of points at whichthe induced or armature winding of the motor is. short-circuited. Bydoing this the output of the motor can be considerably increased and itspower factor and efliciency are improved.

My invention therefore consists in combining with an alternating fieldan induced memher or armature which is uncommuted at starting, aconductor containing a resistance andconnected to said member at aplurality of points at starting the motor, a second con.- ductorinoperative at starting and connected at a plurality of additionalpoints to said member, and means for rendering a second cond uctoroperative to short-circuit said member.

Referring now to the drawing herewith, which shows one type ofinduction-motor embodying my invention, 10 indicates the core of themotor-field, which is provided with three coils or windings l1. Each'ofthese coils 11 is connected to one of the main-line conductors 12, andthe other end of each of the coils is connected to a common conductor13, thus forming a three-phase motor-field having a connection wellknown in the art.

15 is the core of the induced member or armature of the motor. Thearmature-winding is of the continuous type and is composed of aplurality of coils 16, connected in series. At fixed points between thecoils 16 are electrically-connected leads 17, leading to contactplates18, adapted to be connected together by a conducting-ring 19 to providea large number of short circuits for the armaturecoils, as hereinafterdescribed. Three shortcircuiting conductors 20 are also provided and areconnected at three equidistant fixed points to the armature-winding.These three conductors 20 are connected to the three divisions 21 of anadjustable resistance of any desired character. These resistancedivisions 21 are connected to contacts 22. Opencircu1t contacts 23 arealso provided. The

contacts 22 and 23 are circularly arranged within the reach of theswitch-arm 24, which is thus adapted to open the circuit through theconductor 20 and to vary the amount of resistance in such circuit, asdesired.

In the operation of my invention I prefer to start the motor with theresistance 21 completely cut into circuit, with the armaturewinding andthe ring 19 out of contact with the contactplates 18. The resistancethus included in the armature-circuit reduces the starting-current andincreases the starting torque, as is well known in this art. As themotor approaches normal running speed the resistance 21 is graduallyexcluded from the circuit through the conductors 20, thus convertingsuch circuit into a short circuit for the armature, and when normalspeed has been attained the conducting-ring 19 is brought by anysuitable means into contact with the plates 18, thus introducing intothe induced circuit a number of additional short circuits of very lowresistance.

It will be evident that either member of my motor may be the rotarymember, that it may be energized by polyphase alternating current of anydesired number of phases, thatthe conducting-ring 19 may be actuated toclose the short circuits through the leads 17 by any suitable means, andthat the variable resistance 21, so long as it is electrically connectedwith fixed points of the armature-winding,-

may rotate with the armature or' not, as desired, it being onlynecessary to vary the details of construction of the motor as thevarying circumstances require. Such variations may be made withoutdeparting in the least from the principle of my invention.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent of the United States, is

1. The combination with a field adapted to be energized by polyphasealternating current, of an induced member, a conductor electricallyconnected in polyphase relation to said member at a plurality of pointsat starting,

and a second conductor inoperative at starting and adapted to beconnected at a plurality of additional points to said member toshortcircuit said member.

2. The combination with a field adapted to be energized by poly 'ihasealternating current, of an induced member, a conductor electricallyconnected in polyphase relation to said member at a plurality of fixedpoints at starting, and a second conductor adapted to be electricallyconnected at a plurality of additional fixed points to said member toshortcircuit said member.

The combination with a field adapted to be energized by polyphasealternatil'ig current, of an induced member, a COIMlLlCtOI containing avariable resistance and electric: lly connected in polyphase relation tosaid member at a plurality of fixed points at starting, and a secondconductor adapted to be electrically connected at a plurality ofadditional fixed points to said member to short-circuit said member.

4. The combination with a field adapted to be energized by polyphasealternating current, of an induced member, a conductor connected inpolyphase relation to said member at a plurality of fixed points atstarting, and a second conductor inoperative at starting and adapted tobe electrically connected at a plurality of additional fixed points tosaid membcr to short-circuit said member.

5. The combination with a field adapted to be energized by polypl'iasealternating current, of an induced member provided with acontinuous-coil winding, a conductor electrically connected in polyphaserelation to said winding at a plurality of points at starting, and asecond conductor inoperative at starting and adapted to be connected ata plurality of additional points to said winding to short-cir cuit saidwinding.

6. The combination with field adapted to be energized by polyphasealternating current,

of an uncon'imuted induced member, a cruiductor electrically connectedin {)OlXDlitLSO relation to said member at a plurality ol. lKlllli'm atstarting, and a second comluctor inopera' tive at starting and adaptedto be connected at a plurality of additional points to said n1ember toshortcircuit said men'lber.

7. The combination wi th a field adapted to be energized by polyphasealternating current, of an unconmnuted induced men'iber provided with acontinuous-coil winding, a eol'iductor containing a variable resistanceand electrically conneeted in polyphase relation to said \vindil'ig at aplurality ol? fixed points at starting, and a second comluctorinoperative at starting and adapted to be connected at a plu rality ofadditional fixed points to said winding to short-circuit said winding.

8. The combination with a field adapted to be energized by polyphasetltQl'liLillHg' current, of an induced member, a conductor electricallyconnected in polyphase relation to said member at a given number offixed points at starting, and a second conductor :ulapted to beelectrically connected at a larger number of additional fixed points tosaid member to short-circuit said member.

5). The combination with a field adapted to be energized by iolyphasealternating current, of an induced member, a comluctor containing avariable resistance and electricallyconnect ed in polyphase relation tosaid member at a given number of fixed points at starting, and a secondconductor adapted to be electrically connected at a larger number ofadditional fixed points to said member to short-circuit said member.

in testimony whereof I have hereunto set my hand and afiixed my seal inthe presence of the two subscribing witnesses.

LEO senii'iLna. it. s. l

Witnesses;

D. C. .IhrrJmmN, J. H. Bnrscm.

